/*
** $Id: liolib.c,v 2.151 2016/12/20 18:37:00 roberto Exp $
** Standard I/O (and system) library
** See Copyright Notice in lua.h
*/

#define liolib_c
#define LUA_LIB

#include "lprefix.h"


#include <ctype.h>
#include <errno.h>
#include <locale.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "lua.h"

#include "lauxlib.h"
#include "lualib.h"




/*
** Change this macro to accept other modes for 'fopen' besides
** the standard ones.
*/
#if !defined(l_checkmode)

/* accepted extensions to 'mode' in 'fopen' */
#if !defined(L_MODEEXT)
#define L_MODEEXT   "b"
#endif

/* Check whether 'mode' matches '[rwa]%+?[L_MODEEXT]*' */
static int l_checkmode( const char* mode ) {
    return ( *mode != '\0' && strchr( "rwa", *( mode++ ) ) != NULL &&
             ( *mode != '+' || ( ++mode, 1 ) ) && /* skip if char is '+' */
             ( strspn( mode, L_MODEEXT ) == strlen( mode ) ) ); /* check extensions */
}

#endif

/*
** {======================================================
** l_popen spawns a new process connected to the current
** one through the file streams.
** =======================================================
*/

#if !defined(l_popen)       /* { */

#if defined(LUA_USE_POSIX)  /* { */

#define l_popen(L,c,m)      (fflush(NULL), popen(c,m))
#define l_pclose(L,file)    (pclose(file))

#elif defined(LUA_USE_WINDOWS)  /* }{ */

#define l_popen(L,c,m)      (_popen(c,m))
#define l_pclose(L,file)    (_pclose(file))

#else               /* }{ */

/* ISO C definitions */
#define l_popen(L,c,m)  \
      ((void)((void)c, m), \
      luaL_error(L, "'popen' not supported"), \
      (FILE*)0)
#define l_pclose(L,file)        ((void)L, (void)file, -1)

#endif              /* } */

#endif              /* } */

/* }====================================================== */


#if !defined(l_getc)        /* { */

#if defined(LUA_USE_POSIX)
#define l_getc(f)       getc_unlocked(f)
#define l_lockfile(f)       flockfile(f)
#define l_unlockfile(f)     funlockfile(f)
#else
#define l_getc(f)       getc(f)
#define l_lockfile(f)       ((void)0)
#define l_unlockfile(f)     ((void)0)
#endif

#endif              /* } */


/*
** {======================================================
** l_fseek: configuration for longer offsets
** =======================================================
*/

#if !defined(l_fseek)       /* { */

#if defined(LUA_USE_POSIX)  /* { */

#include <sys/types.h>

#define l_fseek(f,o,w)      fseeko(f,o,w)
#define l_ftell(f)      ftello(f)
#define l_seeknum       off_t

#elif defined(LUA_USE_WINDOWS) && !defined(_CRTIMP_TYPEINFO) \
   && defined(_MSC_VER) && (_MSC_VER >= 1400)   /* }{ */

/* Windows (but not DDK) and Visual C++ 2005 or higher */
#define l_fseek(f,o,w)      _fseeki64(f,o,w)
#define l_ftell(f)      _ftelli64(f)
#define l_seeknum       __int64

#else               /* }{ */

/* ISO C definitions */
#define l_fseek(f,o,w)      fseek(f,o,w)
#define l_ftell(f)      ftell(f)
#define l_seeknum       long

#endif              /* } */

#endif              /* } */

/* }====================================================== */


#define IO_PREFIX   "_IO_"
#define IOPREF_LEN  (sizeof(IO_PREFIX)/sizeof(char) - 1)
#define IO_INPUT    (IO_PREFIX "input")
#define IO_OUTPUT   (IO_PREFIX "output")


typedef luaL_Stream LStream;


#define tolstream(L)    ((LStream *)luaL_checkudata(L, 1, LUA_FILEHANDLE))

#define isclosed(p) ((p)->closef == NULL)


static int io_type( lua_State* L ) {
    LStream* p;
    luaL_checkany( L, 1 );
    p = ( LStream* )luaL_testudata( L, 1, LUA_FILEHANDLE );

    if ( p == NULL ) {
        lua_pushnil( L );    /* not a file */
    }
    else if ( isclosed( p ) ) {
        lua_pushliteral( L, "closed file" );
    }
    else {
        lua_pushliteral( L, "file" );
    }

    return 1;
}


static int f_tostring( lua_State* L ) {
    LStream* p = tolstream( L );

    if ( isclosed( p ) ) {
        lua_pushliteral( L, "file (closed)" );
    }
    else {
        lua_pushfstring( L, "file (%p)", p->f );
    }

    return 1;
}


static FILE* tofile( lua_State* L ) {
    LStream* p = tolstream( L );

    if ( isclosed( p ) ) {
        luaL_error( L, "attempt to use a closed file" );
    }

    lua_assert( p->f );
    return p->f;
}


/*
** When creating file handles, always creates a 'closed' file handle
** before opening the actual file; so, if there is a memory error, the
** handle is in a consistent state.
*/
static LStream* newprefile( lua_State* L ) {
    LStream* p = ( LStream* )lua_newuserdata( L, sizeof( LStream ) );
    p->closef = NULL;  /* mark file handle as 'closed' */
    luaL_setmetatable( L, LUA_FILEHANDLE );
    return p;
}


/*
** Calls the 'close' function from a file handle. The 'volatile' avoids
** a bug in some versions of the Clang compiler (e.g., clang 3.0 for
** 32 bits).
*/
static int aux_close( lua_State* L ) {
    LStream* p = tolstream( L );
    volatile lua_CFunction cf = p->closef;
    p->closef = NULL;  /* mark stream as closed */
    return ( *cf )( L ); /* close it */
}


static int io_close( lua_State* L ) {
    if ( lua_isnone( L, 1 ) ) { /* no argument? */
        lua_getfield( L, LUA_REGISTRYINDEX, IO_OUTPUT );    /* use standard output */
    }

    tofile( L ); /* make sure argument is an open stream */
    return aux_close( L );
}


static int f_gc( lua_State* L ) {
    LStream* p = tolstream( L );

    if ( !isclosed( p ) && p->f != NULL ) {
        aux_close( L );    /* ignore closed and incompletely open files */
    }

    return 0;
}


/*
** function to close regular files
*/
static int io_fclose( lua_State* L ) {
    LStream* p = tolstream( L );
    int res = fclose( p->f );
    return luaL_fileresult( L, ( res == 0 ), NULL );
}


static LStream* newfile( lua_State* L ) {
    LStream* p = newprefile( L );
    p->f = NULL;
    p->closef = &io_fclose;
    return p;
}


static void opencheck( lua_State* L, const char* fname, const char* mode ) {
    LStream* p = newfile( L );
    p->f = fopen( fname, mode );

    if ( p->f == NULL ) {
        luaL_error( L, "cannot open file '%s' (%s)", fname, strerror( errno ) );
    }
}


static int io_open( lua_State* L ) {
    const char* filename = luaL_checkstring( L, 1 );
    const char* mode = luaL_optstring( L, 2, "r" );
    LStream* p = newfile( L );
    const char* md = mode;  /* to traverse/check mode */
    luaL_argcheck( L, l_checkmode( md ), 2, "invalid mode" );
    p->f = fopen( filename, mode );
    return ( p->f == NULL ) ? luaL_fileresult( L, 0, filename ) : 1;
}


/*
** function to close 'popen' files
*/
static int io_pclose( lua_State* L ) {
    LStream* p = tolstream( L );
    return luaL_execresult( L, l_pclose( L, p->f ) );
}


static int io_popen( lua_State* L ) {
    const char* filename = luaL_checkstring( L, 1 );
    const char* mode = luaL_optstring( L, 2, "r" );
    LStream* p = newprefile( L );
    p->f = l_popen( L, filename, mode );
    p->closef = &io_pclose;
    return ( p->f == NULL ) ? luaL_fileresult( L, 0, filename ) : 1;
}


static int io_tmpfile( lua_State* L ) {
    LStream* p = newfile( L );
    p->f = tmpfile();
    return ( p->f == NULL ) ? luaL_fileresult( L, 0, NULL ) : 1;
}


static FILE* getiofile( lua_State* L, const char* findex ) {
    LStream* p;
    lua_getfield( L, LUA_REGISTRYINDEX, findex );
    p = ( LStream* )lua_touserdata( L, -1 );

    if ( isclosed( p ) ) {
        luaL_error( L, "standard %s file is closed", findex + IOPREF_LEN );
    }

    return p->f;
}


static int g_iofile( lua_State* L, const char* f, const char* mode ) {
    if ( !lua_isnoneornil( L, 1 ) ) {
        const char* filename = lua_tostring( L, 1 );

        if ( filename ) {
            opencheck( L, filename, mode );
        }
        else {
            tofile( L ); /* check that it's a valid file handle */
            lua_pushvalue( L, 1 );
        }

        lua_setfield( L, LUA_REGISTRYINDEX, f );
    }

    /* return current value */
    lua_getfield( L, LUA_REGISTRYINDEX, f );
    return 1;
}


static int io_input( lua_State* L ) {
    return g_iofile( L, IO_INPUT, "r" );
}


static int io_output( lua_State* L ) {
    return g_iofile( L, IO_OUTPUT, "w" );
}


static int io_readline( lua_State* L );


/*
** maximum number of arguments to 'f:lines'/'io.lines' (it + 3 must fit
** in the limit for upvalues of a closure)
*/
#define MAXARGLINE  250

static void aux_lines( lua_State* L, int toclose ) {
    int n = lua_gettop( L ) - 1; /* number of arguments to read */
    luaL_argcheck( L, n <= MAXARGLINE, MAXARGLINE + 2, "too many arguments" );
    lua_pushinteger( L, n ); /* number of arguments to read */
    lua_pushboolean( L, toclose ); /* close/not close file when finished */
    lua_rotate( L, 2, 2 ); /* move 'n' and 'toclose' to their positions */
    lua_pushcclosure( L, io_readline, 3 + n );
}


static int f_lines( lua_State* L ) {
    tofile( L ); /* check that it's a valid file handle */
    aux_lines( L, 0 );
    return 1;
}


static int io_lines( lua_State* L ) {
    int toclose;

    if ( lua_isnone( L, 1 ) ) {
        lua_pushnil( L );    /* at least one argument */
    }

    if ( lua_isnil( L, 1 ) ) { /* no file name? */
        lua_getfield( L, LUA_REGISTRYINDEX, IO_INPUT ); /* get default input */
        lua_replace( L, 1 ); /* put it at index 1 */
        tofile( L ); /* check that it's a valid file handle */
        toclose = 0;  /* do not close it after iteration */
    }
    else {   /* open a new file */
        const char* filename = luaL_checkstring( L, 1 );
        opencheck( L, filename, "r" );
        lua_replace( L, 1 ); /* put file at index 1 */
        toclose = 1;  /* close it after iteration */
    }

    aux_lines( L, toclose );
    return 1;
}


/*
** {======================================================
** READ
** =======================================================
*/


/* maximum length of a numeral */
#if !defined (L_MAXLENNUM)
#define L_MAXLENNUM     200
#endif


/* auxiliary structure used by 'read_number' */
typedef struct {
    FILE* f;  /* file being read */
    int c;  /* current character (look ahead) */
    int n;  /* number of elements in buffer 'buff' */
    char buff[L_MAXLENNUM + 1];  /* +1 for ending '\0' */
} RN;


/*
** Add current char to buffer (if not out of space) and read next one
*/
static int nextc( RN* rn ) {
    if ( rn->n >= L_MAXLENNUM ) { /* buffer overflow? */
        rn->buff[0] = '\0';  /* invalidate result */
        return 0;  /* fail */
    }
    else {
        rn->buff[rn->n++] = rn->c;  /* save current char */
        rn->c = l_getc( rn->f ); /* read next one */
        return 1;
    }
}


/*
** Accept current char if it is in 'set' (of size 2)
*/
static int test2( RN* rn, const char* set ) {
    if ( rn->c == set[0] || rn->c == set[1] ) {
        return nextc( rn );
    }
    else {
        return 0;
    }
}


/*
** Read a sequence of (hex)digits
*/
static int readdigits( RN* rn, int hex ) {
    int count = 0;

    while ( ( hex ? isxdigit( rn->c ) : isdigit( rn->c ) ) && nextc( rn ) ) {
        count++;
    }

    return count;
}


/*
** Read a number: first reads a valid prefix of a numeral into a buffer.
** Then it calls 'lua_stringtonumber' to check whether the format is
** correct and to convert it to a Lua number
*/
static int read_number( lua_State* L, FILE* f ) {
    RN rn;
    int count = 0;
    int hex = 0;
    char decp[2];
    rn.f = f;
    rn.n = 0;
    decp[0] = lua_getlocaledecpoint();  /* get decimal point from locale */
    decp[1] = '.';  /* always accept a dot */
    l_lockfile( rn.f );

    do {
        rn.c = l_getc( rn.f );
    }
    while ( isspace( rn.c ) );   /* skip spaces */

    test2( &rn, "-+" ); /* optional signal */

    if ( test2( &rn, "00" ) ) {
        if ( test2( &rn, "xX" ) ) {
            hex = 1;    /* numeral is hexadecimal */
        }
        else {
            count = 1;    /* count initial '0' as a valid digit */
        }
    }

    count += readdigits( &rn, hex ); /* integral part */

    if ( test2( &rn, decp ) ) { /* decimal point? */
        count += readdigits( &rn, hex );    /* fractional part */
    }

    if ( count > 0 && test2( &rn, ( hex ? "pP" : "eE" ) ) ) { /* exponent mark? */
        test2( &rn, "-+" ); /* exponent signal */
        readdigits( &rn, 0 ); /* exponent digits */
    }

    ungetc( rn.c, rn.f ); /* unread look-ahead char */
    l_unlockfile( rn.f );
    rn.buff[rn.n] = '\0';  /* finish string */

    if ( lua_stringtonumber( L, rn.buff ) ) { /* is this a valid number? */
        return 1;    /* ok */
    }
    else {  /* invalid format */
        lua_pushnil( L ); /* "result" to be removed */
        return 0;  /* read fails */
    }
}


static int test_eof( lua_State* L, FILE* f ) {
    int c = getc( f );
    ungetc( c, f ); /* no-op when c == EOF */
    lua_pushliteral( L, "" );
    return ( c != EOF );
}


static int read_line( lua_State* L, FILE* f, int chop ) {
    luaL_Buffer b;
    int c = '\0';
    luaL_buffinit( L, &b );

    while ( c != EOF && c != '\n' ) { /* repeat until end of line */
        char* buff = luaL_prepbuffer( &b ); /* preallocate buffer */
        int i = 0;
        l_lockfile( f ); /* no memory errors can happen inside the lock */

        while ( i < LUAL_BUFFERSIZE && ( c = l_getc( f ) ) != EOF && c != '\n' ) {
            buff[i++] = c;
        }

        l_unlockfile( f );
        luaL_addsize( &b, i );
    }

    if ( !chop && c == '\n' ) { /* want a newline and have one? */
        luaL_addchar( &b, c );    /* add ending newline to result */
    }

    luaL_pushresult( &b ); /* close buffer */
    /* return ok if read something (either a newline or something else) */
    return ( c == '\n' || lua_rawlen( L, -1 ) > 0 );
}


static void read_all( lua_State* L, FILE* f ) {
    size_t nr;
    luaL_Buffer b;
    luaL_buffinit( L, &b );

    do {  /* read file in chunks of LUAL_BUFFERSIZE bytes */
        char* p = luaL_prepbuffer( &b );
        nr = fread( p, sizeof( char ), LUAL_BUFFERSIZE, f );
        luaL_addsize( &b, nr );
    }
    while ( nr == LUAL_BUFFERSIZE );

    luaL_pushresult( &b ); /* close buffer */
}


static int read_chars( lua_State* L, FILE* f, size_t n ) {
    size_t nr;  /* number of chars actually read */
    char* p;
    luaL_Buffer b;
    luaL_buffinit( L, &b );
    p = luaL_prepbuffsize( &b, n ); /* prepare buffer to read whole block */
    nr = fread( p, sizeof( char ), n, f ); /* try to read 'n' chars */
    luaL_addsize( &b, nr );
    luaL_pushresult( &b ); /* close buffer */
    return ( nr > 0 ); /* true iff read something */
}


static int g_read( lua_State* L, FILE* f, int first ) {
    int nargs = lua_gettop( L ) - 1;
    int success;
    int n;
    clearerr( f );

    if ( nargs == 0 ) { /* no arguments? */
        success = read_line( L, f, 1 );
        n = first + 1; /* to return 1 result */
    }
    else {   /* ensure stack space for all results and for auxlib's buffer */
        luaL_checkstack( L, nargs + LUA_MINSTACK, "too many arguments" );
        success = 1;

        for ( n = first; nargs-- && success; n++ ) {
            if ( lua_type( L, n ) == LUA_TNUMBER ) {
                size_t l = ( size_t )luaL_checkinteger( L, n );
                success = ( l == 0 ) ? test_eof( L, f ) : read_chars( L, f, l );
            }
            else {
                const char* p = luaL_checkstring( L, n );

                if ( *p == '*' ) {
                    p++;    /* skip optional '*' (for compatibility) */
                }

                switch ( *p ) {
                case 'n':  /* number */
                    success = read_number( L, f );
                    break;

                case 'l':  /* line */
                    success = read_line( L, f, 1 );
                    break;

                case 'L':  /* line with end-of-line */
                    success = read_line( L, f, 0 );
                    break;

                case 'a':  /* file */
                    read_all( L, f ); /* read entire file */
                    success = 1; /* always success */
                    break;

                default:
                    return luaL_argerror( L, n, "invalid format" );
                }
            }
        }
    }

    if ( ferror( f ) ) {
        return luaL_fileresult( L, 0, NULL );
    }

    if ( !success ) {
        lua_pop( L, 1 ); /* remove last result */
        lua_pushnil( L ); /* push nil instead */
    }

    return n - first;
}


static int io_read( lua_State* L ) {
    return g_read( L, getiofile( L, IO_INPUT ), 1 );
}


static int f_read( lua_State* L ) {
    return g_read( L, tofile( L ), 2 );
}


static int io_readline( lua_State* L ) {
    LStream* p = ( LStream* )lua_touserdata( L, lua_upvalueindex( 1 ) );
    int i;
    int n = ( int )lua_tointeger( L, lua_upvalueindex( 2 ) );

    if ( isclosed( p ) ) { /* file is already closed? */
        return luaL_error( L, "file is already closed" );
    }

    lua_settop( L, 1 );
    luaL_checkstack( L, n, "too many arguments" );

    for ( i = 1; i <= n; i++ ) { /* push arguments to 'g_read' */
        lua_pushvalue( L, lua_upvalueindex( 3 + i ) );
    }

    n = g_read( L, p->f, 2 ); /* 'n' is number of results */
    lua_assert( n > 0 ); /* should return at least a nil */

    if ( lua_toboolean( L, -n ) ) { /* read at least one value? */
        return n;    /* return them */
    }
    else {  /* first result is nil: EOF or error */
        if ( n > 1 ) { /* is there error information? */
            /* 2nd result is error message */
            return luaL_error( L, "%s", lua_tostring( L, -n + 1 ) );
        }

        if ( lua_toboolean( L, lua_upvalueindex( 3 ) ) ) { /* generator created file? */
            lua_settop( L, 0 );
            lua_pushvalue( L, lua_upvalueindex( 1 ) );
            aux_close( L ); /* close it */
        }

        return 0;
    }
}

/* }====================================================== */


static int g_write( lua_State* L, FILE* f, int arg ) {
    int nargs = lua_gettop( L ) - arg;
    int status = 1;

    for ( ; nargs--; arg++ ) {
        if ( lua_type( L, arg ) == LUA_TNUMBER ) {
            /* optimization: could be done exactly as for strings */
            int len = lua_isinteger( L, arg )
                      ? fprintf( f, LUA_INTEGER_FMT,
                                 ( LUAI_UACINT )lua_tointeger( L, arg ) )
                      : fprintf( f, LUA_NUMBER_FMT,
                                 ( LUAI_UACNUMBER )lua_tonumber( L, arg ) );
            status = status && ( len > 0 );
        }
        else {
            size_t l;
            const char* s = luaL_checklstring( L, arg, &l );
            status = status && ( fwrite( s, sizeof( char ), l, f ) == l );
        }
    }

    if ( status ) {
        return 1;    /* file handle already on stack top */
    }
    else {
        return luaL_fileresult( L, status, NULL );
    }
}


static int io_write( lua_State* L ) {
    return g_write( L, getiofile( L, IO_OUTPUT ), 1 );
}


static int f_write( lua_State* L ) {
    FILE* f = tofile( L );
    lua_pushvalue( L, 1 ); /* push file at the stack top (to be returned) */
    return g_write( L, f, 2 );
}


static int f_seek( lua_State* L ) {
    static const int mode[] = {SEEK_SET, SEEK_CUR, SEEK_END};
    static const char* const modenames[] = {"set", "cur", "end", NULL};
    FILE* f = tofile( L );
    int op = luaL_checkoption( L, 2, "cur", modenames );
    lua_Integer p3 = luaL_optinteger( L, 3, 0 );
    l_seeknum offset = ( l_seeknum )p3;
    luaL_argcheck( L, ( lua_Integer )offset == p3, 3,
                   "not an integer in proper range" );
    op = l_fseek( f, offset, mode[op] );

    if ( op ) {
        return luaL_fileresult( L, 0, NULL );    /* error */
    }
    else {
        lua_pushinteger( L, ( lua_Integer )l_ftell( f ) );
        return 1;
    }
}


static int f_setvbuf( lua_State* L ) {
    static const int mode[] = {_IONBF, _IOFBF, _IOLBF};
    static const char* const modenames[] = {"no", "full", "line", NULL};
    FILE* f = tofile( L );
    int op = luaL_checkoption( L, 2, NULL, modenames );
    lua_Integer sz = luaL_optinteger( L, 3, LUAL_BUFFERSIZE );
    int res = setvbuf( f, NULL, mode[op], ( size_t )sz );
    return luaL_fileresult( L, res == 0, NULL );
}



static int io_flush( lua_State* L ) {
    return luaL_fileresult( L, fflush( getiofile( L, IO_OUTPUT ) ) == 0, NULL );
}


static int f_flush( lua_State* L ) {
    return luaL_fileresult( L, fflush( tofile( L ) ) == 0, NULL );
}


/*
** functions for 'io' library
*/
static const luaL_Reg iolib[] = {
    {"close", io_close},
    {"flush", io_flush},
    {"input", io_input},
    {"lines", io_lines},
    {"open", io_open},
    {"output", io_output},
    {"popen", io_popen},
    {"read", io_read},
    {"tmpfile", io_tmpfile},
    {"type", io_type},
    {"write", io_write},
    {NULL, NULL}
};


/*
** methods for file handles
*/
static const luaL_Reg flib[] = {
    {"close", io_close},
    {"flush", f_flush},
    {"lines", f_lines},
    {"read", f_read},
    {"seek", f_seek},
    {"setvbuf", f_setvbuf},
    {"write", f_write},
    {"__gc", f_gc},
    {"__tostring", f_tostring},
    {NULL, NULL}
};


static void createmeta( lua_State* L ) {
    luaL_newmetatable( L, LUA_FILEHANDLE ); /* create metatable for file handles */
    lua_pushvalue( L, -1 ); /* push metatable */
    lua_setfield( L, -2, "__index" ); /* metatable.__index = metatable */
    luaL_setfuncs( L, flib, 0 ); /* add file methods to new metatable */
    lua_pop( L, 1 ); /* pop new metatable */
}


/*
** function to (not) close the standard files stdin, stdout, and stderr
*/
static int io_noclose( lua_State* L ) {
    LStream* p = tolstream( L );
    p->closef = &io_noclose;  /* keep file opened */
    lua_pushnil( L );
    lua_pushliteral( L, "cannot close standard file" );
    return 2;
}


static void createstdfile( lua_State* L, FILE* f, const char* k,
                           const char* fname ) {
    LStream* p = newprefile( L );
    p->f = f;
    p->closef = &io_noclose;

    if ( k != NULL ) {
        lua_pushvalue( L, -1 );
        lua_setfield( L, LUA_REGISTRYINDEX, k ); /* add file to registry */
    }

    lua_setfield( L, -2, fname ); /* add file to module */
}


LUAMOD_API int luaopen_io( lua_State* L ) {
    luaL_newlib( L, iolib ); /* new module */
    createmeta( L );
    /* create (and set) default files */
    createstdfile( L, stdin, IO_INPUT, "stdin" );
    createstdfile( L, stdout, IO_OUTPUT, "stdout" );
    createstdfile( L, stderr, NULL, "stderr" );
    return 1;
}

